Textures Not Rendering Blender 2.8
The reason why they don't show up is that the UV unwrap is not done properly. 

If you select the eyes in Edit Mode, you can see that the vertices are all in the bottom right corner, where the texture is transparent (so there is no color data). To change that, just position the vertices on the eyes in the texture and you are all set!

This is what you have right now (the wrong way):



And this is the right way: